From 1860f37169ddc8abfea2e33a71fab1b9c8433204 Mon Sep 17 00:00:00 2001
From: rimathia <rimathia@users.noreply.github.com>
Date: Thu, 3 Sep 2020 11:47:02 +0200
Subject: [PATCH] use memchr for finding '%' in formatting string in printf.h

---
 include/fmt/printf.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/fmt/printf.h b/include/fmt/printf.h
index 8c28ac232727..ad35d5b82a89 100644
--- a/include/fmt/printf.h
+++ b/include/fmt/printf.h
@@ -474,8 +474,18 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
   const Char* end = parse_ctx_.end();
   auto it = start;
   while (it != end) {
+    if (end - it < 32) {
+      // Use a simple linear search instead of memchr for small strings.
+      it = std::find(it, end, '%');
+    } else {
+      if (!detail::find<false, Char>(it, end, '%', it)) {
+        it = end;
+      }
+    }
+    if (it == end) {
+      continue;
+    }
     char_type c = *it++;
-    if (c != '%') continue;
     if (it != end && *it == c) {
       out = std::copy(start, it, out);
       start = ++it;